Field of the Disclosure
The present disclosure relates to a reflective sheet with a dot-cut pattern for preventing both bright line and bright spot, which is capable of reducing a manufacturing cost and also improving a manufacturing efficiency, and a method of manufacturing the same.
Discussion of the Related Art
With the development of various kinds of mobile electronic equipment such as mobile terminal and notebook computer and a large-sized television, there is an increasing demand on flat panel display devices which are applied thereto.
The flat panel display devices may include a liquid crystal display device (LCD), a plasma display panel (PDP), a field emission display device (FED), an organic light emitting diode display device, and etc.
Among the various flat panel display devices, the LCD device has been widely used in various fields of monitors used for industrial terminal, notebook computer, video game machine, and etc.; mobile terminals such as mobile phone, MP3, PDA, PMP, PSP, mobile game machine, DMB receiver, and etc.; and electric home appliances such as refrigerator, microwave oven, washing machine, and etc. owing to development of mass production technology, easiness of driving means, high resolution, low power consumption and realization of large size.
The LCD device may include a thin film transistor (TFT) formed in each of pixels arranged in a matrix configuration, wherein a light transmittance may be controlled by a video signal applied to each pixel, to thereby display an image.
The LCD device may include a liquid crystal panel, a backlight unit for supplying light to the liquid crystal panel, and a driving circuit, wherein the liquid crystal panel may include a lower substrate, an upper substrate, and a liquid crystal layer formed between the lower and upper substrates.
The liquid crystal panel cannot emit light in itself. Thus, the liquid crystal panel inevitably requires a light source for supplying the light. That is, the backlight unit is provided at a lateral side or rear side of the liquid crystal panel, whereby the light emitted from the backlight unit is supplied to the liquid crystal panel.
FIG. 1 illustrates an LCD device including a reflective sheet according to the related art.
As shown in FIG. 1, the LCD device may include a liquid crystal panel 60 provided with a plurality of liquid crystal cells arranged in a matrix configuration so as to display an image; a backlight unit for supplying light to the liquid crystal panel 60; a cover bottom 10 for receiving the backlight unit therein; a top case (not shown); and a driving circuit (not shown) for driving the liquid crystal panel 60 and a light source of the backlight unit.
The liquid crystal panel 60 may include a lower substrate 62, an upper substrate 64, and a liquid crystal layer 66, wherein the liquid crystal layer 66 is interposed between the lower and upper substrates 62 and 64 bonded to each other. The liquid crystal panel 60 cannot emit light in itself, whereby the liquid crystal panel 60 needs the light source. In this case, the light emitted from the backlight unit including the light source positioned at a rear surface of the liquid crystal panel 60 is supplied to the liquid crystal panel 60. FIG. 1 shows a direct-type backlight unit in which a light source of light emitting diode (LED) 20 is used.
To improve picture quality of the image displayed on the display panel 60, there are many factors that need to be considered. One of the most important factors is to uniformly maintain luminance of the light emitted to the liquid crystal panel 60. That is, the uniform luminance of light supplied to the liquid crystal panel 60 enables to realize the good picture quality of image.
To this end, the backlight unit may include a plurality of LEDs 20, a diffusion plate 40, a plurality of optical sheets 50, and a reflective sheet 30.
On the bottom of the cover bottom 10, there are the plurality of LEDs 20 provided in an array type. The plurality of optical sheets 50 are provided on the diffusion plate 40. The plurality of optical sheets 50 may include a diffuser sheet, a prism sheet, and a reflective polarizing film (DBEF, dual brightness enhancement film).
FIG. 2 illustrates an ink pattern formed at a lateral side of the reflective sheet according to the related art. FIG. 3 illustrates a method of manufacturing the reflective sheet shown in FIG. 1 according to the related art.
As shown in FIGS. 2 and 3, the reflective sheet 30 may include a first surface (bottom surface) 32 provided on the bottom of the cover bottom 10, and a second surface (lateral surface) 34 provided at a lateral side of the cover bottom 10. The first surface 32 of the reflective sheet 30 is provided with a hole 38 for exposing the LED 20 therethrough. The reflective sheet 30 is attached to the bottom and lateral surfaces of the cover bottom 10 so as to reflect the light generated in the LED 20 toward the liquid crystal panel 60.
To prevent both bright line and bright spot of the light generated in the LED 20, a dot pattern of grey-colored or black-colored ink is printed on the second surface 34 of the reflective sheet 30, that is, the lateral surface of the reflective sheet 30 so that it is possible to realize uniform luminance of the light reflected on the lateral surface of the cover bottom 10. In this case, the reflective sheet 30 is provided with a half-cut pattern 39 which enables to arrange the reflective sheet 30 along the profile of lateral surface of bottom surface of the cover bottom 10.
A method of manufacturing the reflective sheet 30 according to the related art will be described as follows.
First, the hole 38 for exposing the LED 20 and the half-cut pattern 39 for making the reflective sheet 30 bent along the profile of the cover bottom 10 are formed for a first manufacturing process.
Then, for a second manufacturing process, the dot pattern 34 is printed on the lateral surface of the reflective sheet 30 so as to overcome the problems related with the bright line and bright spot which might occur in the direct-type backlight unit.
The above two manufacturing processes are carried out to manufacture the reflective sheet 30, which causes the lowering of manufacturing efficiency and the increase of manufacturing cost.